Close Ratio Box?

[v1nn13]

Hi all,
Whilst out riding with my friend (on an L9) i noticed he could get off the line alot faster than i can...i'm standing there like a lemon trying to get off the clutch... its also a bit toad pulling away up hills and whilst carrying pillion

We both run standard sprocket sizes but mine seems to go well through 60mph before she hits redline in first! After letting my mate have a go on mine, he confirmed that my first gear was very tall and all gears felt alot closer than his.

Is it just me or does this sound like the close-ratio box from the SP model?

Cheers

[RedexRobB]

Could be, check out the thread on the J model for some pointers.

[v1nn13]

Have done, but found no definite way of checking =/.
Bit annoying really as i use it for everyday use and sitting at around 8-9k RPM at 70

[cargo]

Stock front sprocket with a SP close ratio gearbox is 16 teeth.........................so go count em

[v1nn13]

Well I know it's got a 16 front because I've just put one on aswell as a 43t rear. That knocks the rpm @70 down to 7k.
When I bought the bike it had 15 front and 45 rear and would sit at around 8-9k rpm @ 70. The bike itself was bought as an H1 but looks like someone in the past has played around with the engine.

Just wanted to see what you guys thought as was thinking of changing the gearbox out for a standard L1 one.

[cargo]

you've got a 16 on the front along with a 43 on the rear....................and because you cant get off to a quick standing start you reckon you've got a SP gearbox.


Your an idiot................plain and simple

And a liar too because your first post says you were using standard sprockets

[banner001]

damn, i HATE to agree with my friend cargo...but he is not wrong.

you have upped your gearing from a top speed of 135mph to 150mph...and you wonder why you are accelerating slower?

even a 80bhp race engine will struggle to use that gearing...

[cargo]

I am never wrong......................just marginally incorrect on occasion

[banner001]

Have done, but found no definite way of checking =/.
Bit annoying really as i use it for everyday use and sitting at around 8-9k RPM at 70

10k rpm for stock gearing = 70mph in 3rd gear, your bike will hit 70mph in 3rd gear at 9k rpm.

[v1nn13]

Christ sake...I post an honest question on here, and you mock me. If you read the last post I clearly said I have just put on a 16t sprocket and 43t rear to account for the high revving 6th gear, the original post said I had original sprockets for my bike (ie 15 & 45) and it had a tall first gear. I don't appreciate being called a liar.

With the 15 front and the 45 rear my 1st gear would do about 65ish mph at redline and I had a top speed of around 120-mph (6th gear at redline)
With the 16 front and the 45 rear there wasn't a lot of noticeable difference.
With the 16 front and the 43 my 1st gear does 70+ mph and 6th now sits at 7k rpm @ 70mph (which is what my mates l9 sits at)

All I wanted to know is why my bike, on standard sprockets (15t front and 45t rear), had a very tall 1st gear and redlined at 120mph in 6th

[cargo]

Hi all,
Whilst out riding with my friend (on an L9) i noticed he could get off the line alot faster than i can...i'm standing there like a lemon trying to get off the clutch... its also a bit toad pulling away up hills and whilst carrying pillion

We both run standard sprocket sizes but mine seems to go well through 60mph before she hits redline in first! After letting my mate have a go on mine, he confirmed that my first gear was very tall and all gears felt alot closer than his.

Is it just me or does this sound like the close-ratio box from the SP model?

Cheers

Your post very clearly says that you run standard sprockets...............................





then you tell us............... you have 16/43 sprockets...................................




IF you had a first gear acceleration problem with 15/45..................................16/43 will make it even worse................regardless of what gearbox you have

A SP gearbox running 15/45 will actually be accelerate quite well from a standing start because that is much lower gearing that standard SP sprockets 16/45)

I stand by what I said

[v1nn13]

I know the sprockets I have chosen will make acceleration worse. And I knew that when I fitted them. I'm not asking about the gearing on my current sprockets, only on the standards ones.

But I can only tell you what I know...with 15t front and 45t rear my 1st gear was taller than an L9 with the same sprockets...and my 6th gear would redline at 120ish mph.

I have no idea of the gearing of an SP box or whether there was a difference between the H and the L gearbox...that's why I posted this question.

[cargo]

None so blind as those that cannot or will not see.


I've nothing further to add I cannot explain gearboxes and gearing any better for you than I already have

[v1nn13]

Using the information i found posted somewhere on this forum, where the left is the J gearing and the right is the H gearing,

Screen Shot 2013-10-14 at 21.53.42.png

I popped that into the gear/speed calculator found from here viewtopic.php?f=55&t=2830, comparing set ups i have tried (15t/45t), (16t/45t) and (16t/43t). This gave me the speed read outs i get for different sprocket setups

Screen Shot 2013-10-14 at 22.41.01.png

Screen Shot 2013-10-14 at 22.41.20.png

All of which add up to the results i get from my bike.
I have only recently put the 16/43 sprocket setup on for now as motorway journeys kill fuel on a lower gearing.

Sorry if none of my previous post made sense, I'm not too good at explaining what i mean.